Power electronics device and its cooling arrangement

Abstract

Liquid-cooled power unit of a power electronics device, which power unit includes at least two power modules, the cooling surface of which power modules is provided with pin-type protrusions and which power modules are fixed to the frame part of the power unit. A liquid duct is arranged inside the frame part of the power unit, and the power modules are fixed to the points of the apertures situated in the frame part on both sides of the liquid duct in such a way that the pin-type protrusions of the power modules are situated in the liquid duct. A wedge-shaped part is disposed in the liquid duct, which wedge-shaped part includes a wedge-shaped front part for spreading the liquid flow into two essentially equal flows at the point of the power modules.

Description

FIELD OF TECHNOLOGY[0001]The object of this invention is an arrangement for cooling the components in a power electronics device, such as in a frequency converter.[0002]More particularly the object of the invention is an arrangement for the cooling of power components connected in parallel.PRIOR ART[0003]The general development trend of power electronics devices, such as frequency converters, is an increase in power density. It is known in the art that handling of high power in a small-sized device requires effective cooling of the components handling the power, which best succeeds with liquid cooling, i.e. by transferring the dissipation power produced in the components via liquid circulating in the device to outside the device.[0004]For reasons of cost, liquid cooling is most often used only in high-powered devices, e.g. in frequency converters of over 100 kW. Owing to the limited performance of an individual power semiconductor component, at high powers they must be connected in ...

AI Technical Summary

Benefits of technology

The patent describes a cooling system for power modules that uses liquid flow to cool them efficiently. The system has special features that create turbulence in the liquid flow, which enhances the cooling power. The arrangement also has a frame part that is designed to prevent liquid leaks and can be made using low-cost manufacturing methods. The precise shaping of the liquid duct is important for achieving symmetrical liquid flow. The frame part can be a single-piece or composed of two halves that are fixed together. The technical effects of the system are improved cooling performance, reduced leakage risk, and cost-effective manufacturing.

Problems solved by technology

Owing to the limited performance of an individual power semiconductor component, at high powers they must be connected in parallel, either in such a way that there are a number of components in parallel in the same device or by connecting whole devices in parallel to supply the same load.

Parallel connection of components in the same device is problematic particularly because each differently-powered device must have its own mechanical structural unit constructed.

In the case of power components connected in parallel, as is known, the requirement can result in the selection of components and / or the use of additional chokes limiting current imbalances e.g. according to patent publication U.S. Pat. No. 6,985,371, both of which methods are problematic from the viewpoint of manufacture and servicing as well as of costs.

With a cooler according to prior art, inside which ducts are arranged for the flow of cooling liquid, the evenness of the flows in all the ducts and turbulence that enhances cooling are difficult to achieve, as is known in the art, which can cause problems in the cooling of components connected in parallel.

Thermotechnically this sort of location is often problematic, because the internal temperature of a power component can, despite effective liquid cooling, rise to be high, e.g. to 100° C., in which case the temperature can also rise in the immediate surroundings of the component, such as in the cooler and via it also in the air space surrounding the power component, to be detrimentally high from the viewpoint of the lifetime of the components disposed on the circuit boards.

For this reason a fan disposed in the interior space of the device is generally used for cooling the components disposed on a circuit board, which is a problem from the viewpoint of the reliability of the whole device because of the limited lifetime of fans.

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